Coping with Extremes

By Carolyn Rumery Betz

Drought, heat waves, heavy rainfall and other extreme weather events are likely to become more common in Wisconsin's future, according to WICCI climate scientists. For example, they say southern Wisconsin will see significant increases in rain events that dump one, two or three inches in a 24-hour period. The state may also see as many as 60 days per year where the temperature tops 90˚F by the end of this century, with more than 14 days over 100˚F. The scientists also expect fewer winter nights below 0˚F.

Steve Vavrus is a senior scientist at the Nelson Institute Center for Climatic Research at the University of Wisconsin-Madison and a member of the WICCI Climate
Working Group. Vavrus has studied extreme events in the United States that occurred over the last century. He is interested in the impacts they pose on ecosystems, agriculture, human health, stormwater management, infrastructure and the economy.

"It's so difficult to give a 'yes' or 'no' answer to the question I frequently get: Can we attribute extreme events to global warming?" says Vavrus. "The answer is usually yes and no. We can never prove that a certain event occurred because the climate is changing, but hopefully, we can determine how much
climate change has loaded the dice for these events to occur."

The Midwest has experienced plenty of extremes in the recent past. The heat wave of 1995 brought temperatures over 100˚F, along with extremely high humidity. More than 750 heat-related deaths were reported in Chicago.

In 2012, the weather was particularly weird in Wisconsin, with record-breaking March temperatures more typical of June and July. A cold snap in April was followed by a heat-wave in July. Madison experienced 104˚F as part of a three-day streak over 100˚. A mild fall followed, with late-November snow falling in the
north on ground that had yet to freeze.

All communities should develop heat wave action plans, stresses Vavrus. During the 2012 heat wave, the city of Madison opened its convention facility as a public cooling center for those with no air conditioning. The city also provided free bus transportation to the downtown location.

Weather forecasting for extreme events has become much more accurate than in the past, according to Vavrus, providing the opportunity to prevent negative health impacts. Organizers of the 2012 Madison Marathon used the forecast of unusually hot weather to make the decision to cancel that year's event. The day turned out to be 94ºF, too risky for a long running event.

"I can't emphasize enough how much that hot weather, which we'll be seeing more of in the future, is a deadly serious health risk," Vavrus says. "Heat action plans can save lives."

Additionally, the apple crop was almost a complete failure in Door County and other parts of the state. The March warming that lured people to break out their shorts and flip flops also encouraged fruit trees to come into blossom — but the cold snap that followed put an abrupt end to the season before the fruit
could even set.

The state has also seen extremes in precipitation in the recent past. The 14 inches of rain that fell over a two-week period in the south central part of the state in 2008 was in sharp contrast to the continuing drought that plagued the northern part of the state, where piers stood high and dry over disappearing lakes. The heavy rain wiped out sections of the interstate, made sewage treatment plants overflow their capacities, and caused $34 million in damage to
municipal infrastructure.

Communities like Spring
Green and Brodhead experienced groundwater flooding, a process by which the water table rises so high that it ponds on the surface. After five months of pooled groundwater in a neighborhood in Spring Green, the Federal Emergency Management Agency (FEMA) spent $5.37 million to buy out 28 homes, the first such action for groundwater flooding in the country. Wisconsin hydrogeologists expect this kind of flooding to occur more frequently in the future.

Wisconsin should be proactive in developing adaptation strategies to cope with extreme events, according to climate experts.

David S. Liebl, an outreach specialist with University of Wisconsin-Cooperative Extension and a WICCI member, is working with county Extension agents to
improve their understanding of climate change so they can help individuals and communities prepare for extreme events.

"From family living agents working with the elderly and vulnerable populations to prepare for heat waves, to agricultural agents working with farmers on installing cooling systems for their cows, Extension agents are in a prime position to help others address vulnerabilities," he says.

Liebl and University of Wisconsin-Madison engineering professor Ken Potter have been working with municipalities to address climate impacts on stormwater infrastructure, their area of specialty. They believe that some communities will need to handle larger stormwater flows to prevent flooding, combined stormwater
overflows and the health-related consequences from these events, such as mosquito infestations and mold growth in homes.